Christmas tree worm

The worms that make Christmas What could be more festive than a Christmas tree? Coral reefs decked with Christmas tree worms are quite a sight. The worms put out paired tentacles covered in feather-like structures called ‘radioles’ which are spiralled in the shape of Christmas trees. Added to this, each worm has tentacles of a different, vibrant colour and pattern, so groups resemble festive decorations! Christmas tree worms are found in coral reefs worldwide. They thrive on the unspoilt reefs of Bermuda in the British overseas territories. The worm itself lives in a hard tube it has made, usually inside a hole bored into a live coral.

Fast Facts

Latin name: Spirobranchus giganteus

Notable feature: Colourful, Christmas tree-shaped tentacles.

Rarity in the UK: Rare / Common

Where in the UK: Found in tropical oceans, including around many UK overseas territories.

Multi-purpose tentacles

The attractive tentacles we can see are used for feeding, by filtering plankton from the water, as well as for breathing like gills. The radioles are also scattered with light-sensitive molecules, helping the Christmas tree worms to detect the shadow of predators. If a fish comes near, the worm can quickly retract its tentacles so they don’t get nibbled off. They also react to touch. Predators can’t reach them inside their coral home.

Survivors of the seas

Christmas tree worms survive well in their safe abodes. Scientists have found out from the growth rings of their tubes that they can live for 10 to 40 years!

Christmas tree worms aren’t currently under threat of extinction, however loss of habitat, coral bleaching, changes in water temperatures and collection for the aquarium industry affect their numbers locally.

Fun fact

The alien forests in the movie Avatar featured touch-sensitive plants which were inspired by Christmas tree worms.

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